Two-dimensional rectangular bismuth bilayer:A novel dual topological insulator  

作　　者：Shengshi Li Weixiao Ji Jianping Zhang Yaping Wang Changwen Zhang Shishen Yan 

机构地区：[1]Spintronics Institute,School of Physics and Technology,University of Jinan,Jinan 250022,China [2]State Key Lab of Crystal Materials and Institute of Crystal Materials,Shandong University,Jinan 250100,China

出　　处：《Frontiers of physics》2023年第4期239-247,共9页物理学前沿（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.12004137);the Taishan Scholar Project of Shandong Province(No.ts20190939);the Natural Science Foundation of Shandong Province(Grant No.ZR2020QA052).

摘　　要：Dual topological insulator(DTI),which simultaneously hosts topological insulator(TI)and topological crystalline insulator(TCI)phases,has attracted extensive attention since it has a better robustness of topological nature and broad application prospects in spintronics.However,the realization of DTI phase in two-dimensional(2D)system is extremely scarce.By first-principles calculations,we predict that the 2D rectangular bismuth(R–Bi)bilayer is a novel DTI,featured by topological invariant=1,mirror Chern number C_(M)=–1,and metallic edge states within the bulk band gap.More interestingly,the TCI phase in bilayer is protected by horizontal glide mirror symmetries,rather than the usual mirror symmetry.The bulk band gap can be effectively tuned by vertical electric field and strain.Besides,the electric field can trigger the transition between TI and metallic phases for the bilayer,accompanied by the annihilation of TCI phase.On this basis,a topological field effect transistor is proposed,which can rapidly manipulate spin and charge carriers via electric field.The KBr(110)surface is demonstrated as an ideal substrate for the deposition of bilayer.These findings provide not only a new strategy for exploiting 2D DTI,but also a promising candidate for spintronic applications.

关 键 词：dual topological insulator Bi bilayer glide mirror symmetry first-principles calculations 

分 类 号：O469[理学—凝聚态物理]